Here.

streams/src/streams/Main.java

@@ -2,6 +2,7 @@ package streams;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 import tester.Tester;
 
@@ -92,4 +93,34 @@ interface PurchaseDB {
     getPurchasesForSince(List<Integer> customerIds, int numberOfDaysAgo);
 }
 
-class Examples {}
+class Victims implements CustomerDB {
+    Map<Integer, Customer> victims;
+
+    Victims() {}
+
+    public Optional<Customer> getCustomerById(int id) {
+        return Optional.ofNullable(this.victims.get(id));
+    }
+
+    public List<Customer> getAllCustomers() {
+        return this.victims.values().stream().toList();
+    }
+}
+
+class Examples {
+    Customer borace, germany, vietnam;
+    Inventory cabbages, cinderBlocks;
+    LineItem lottaCabbages, oneCinderBlock;
+    Purchase profit;
+
+    void init() {
+        borace = new Customer(0, "Borace");
+        borace = new Customer(0, "Germany");
+        borace = new Customer(0, "Vietnam");
+        cabbages = new Inventory(0, "Expensive cabbages.", 28);
+        cinderBlocks = new Inventory(1, "Cinder blocks.", 1);
+        lottaCabbages = new LineItem(0, 54);
+        oneCinderBlock = new LineItem(1, 1);
+        profit = new Purchase(0, List.of(lottaCabbages, oneCinderBlock), 0, 1);
+    }
+}

twentyfortyeight/src/twentyfortyeight/Main.java

@@ -183,7 +183,6 @@ class Grid {
     // Combine numbers that are the same into their sum. Start checking for
     // combinations from the side the direction is to for each row/column.
     void combine(int d) {
-        // Assume left.
         if (d == 0) {
             for (int y = 0; y < this.h; y++) {
                 int prv = this.get(0, y);